Public Events ( Pomoc )

I'm trying to find out why I don't get rewards for some of the public events I've completed. One day I had completed 4 ( 2 in the afternoon and 2 in the evening) with no reward on-site or waiting at the tower. This has happened many times now where friends that have completed the same event all get a reward on-site or at the tower. Another problem I have come across was that I've had 5 exotic weapon bounties, the first time I had 3 to choose from the second I only had two to choose from and the third I was given no option. After completing "a dubious task" and "tolands legacy" I gave up on "a light in the dark" because I didn't want to go thru the third stage. When I got my 4th exotic weapon bounty it gave me the original 3 that I had already selected so I choose " a dubious task" and completed that for a second time. And now for my 5th bounty I have only the original 3 to choose from again. Since I already have 2 "invective" shotguns and the "bad juju" pulse rifle and I'm not interested in the hand cannon from "a light in the dark" how the hell do I get a different bounty? From what I've read each chance at a bounty is supposed to offer me 3 random bounties, which I am yet to see.